The Chaser was formerly Lauren (the player)'s friend Kate, the identity of the player from the first installment of the series, Slender: The Eight Pages.

During Mark's Slender: The Arrival playthrough, he became increasingly irritated by the Chaser - he eventually nicknamed it 'Little Douchebag', due to her annoying ("unfair") in-game behavior. In-game, she seemed to be afraid of or intolerable of light, as directing a focused beam of light in her eyes will incapacitate her as long as it is on her.

Appearance(s)

Kate used to look like a regular teenage girl, until she became the Chaser. She wears a white blood-stained hoodie, bloodied jeans, boots, and a white mask, only revealing her eyes. Her eyes have black circles around them, her black hair is messy and ends in bundled streaks and her hands are coated in blood.

Kate does not make a full physical appearance until the second game, both in her "Chaser" persona and her regular state of being. She is first encountered in the abandoned mines as The Chaser, and Lauren is tasked with keeping her at bay while she attempts to restart several generators around the area in order to use the elevator.

She is later seen in a flashback sequence, during a time prior to her transformation into a proxy. The player takes control of Kate as she makes a futile attempt to shut the Slender Man out of her house (the house seen in the first level of the game), closing every open window and door. However, the Slender Man finds a way inside regardless, and she is forced into her bedroom where the Slender Man follows her, causing her to panic and jump out of the bedroom window before the level ends.

In the Steam version of the game, Kate is encountered in the burned-down shack during the game's end. She appears as her regular persona, crying in one corner of the building. As the player approaches her, she suddenly changes back into her Chaser persona and attacks Lauren. The camera flashes in and out before it switches back to a view of someone's legs on the ground, being slowly dragged away afterwards.

Trivia

Kate is playable in the level 'Genesis' in Slender: The Arrival, where the player relives the original map from Slender: The Eight Pages.

Occasionally, Mark gets the gender confused - during his first playthough of The Arrival, he perceived 'Little Douchebag' as a male; later, when he replayed the game on Hardcore difficulty, he seemed to be somewhat aware (albeit skeptical) of the fact that 'Little Douchebag' is Kate (possibly after taking the fanbase's comments into consideration, or from research); when he later replayed the Steam version of the game on a livestream, he refers to 'Little Douchebag' as 'he' and 'him', implying that he may have forgotten or may still be unsure.

Much of the Slender/creepypasta fanbase originally perceived the Chaser as Jeff The Killer, another well-known creepypasta icon. It was also speculated that this would be the game's portrayal of Masky, a mysterious figure from the Marble Hornets universe. These were later proven false upon the game's release.